He was a reader of SF right from the start of Amazing Stories in 1926 and began corresponding with other fans shortly after addresses started being published in the prozines, thus making him one of the very earliest fen.

Over My Shoulder: Reflections on a Science Fiction Era (Oswald Train: 1983) is his semi-auto-biographical history of small press publishing in the 30s through the 50s.
It is in there where he recalled L. Ron Hubbard as telling him in 1949, "I’d like to start a religion. That’s where the money is.

He began publishing professionally in 1930 with the story “The Man with the Silver Disc.” In 1946, he started up Fantasy Press, one of the pioneering sfsmall presses, publishing works by Jack Williamson, L. Sprague de Camp, Stanley Weinbaum, and others in hardcover. He edited Of Worlds Beyond: The Science of Science Fiction Writing (Fantasy Press, 1947), the first book-length work on SF writing from the point of view of professionals. He also published critical works about the history of modern science fiction. In the 1980s, he returned to writing, publishing several novels.